1. Field of the Invention
The present invention relates to a spectrometer apparatus using a continuous wave laser and a photomultiplier tube.
2. Description of the Related Art
Conventionally, according to the real-time measurement of a single particle in atmospheric fine particle using a LIBS (Laser-Induced Breakdown Spectroscopy is reported by G. A. Lithgow et al. (“Ambient measurements of metal-containing PM2.5 in an urban environment using laser-induced breakdown spectroscopy”, Atmos. Environ. 38, 3319-3328, 2004) and Carranza et al. (“On-line analysis of ambient air aerosols using laser-induced breakdown spectroscopy”, Spectrochim. Part B. 56, 851-864, 2001), particles have been measured through a free-firing mode in which the path of fine particle floating at the air is centralized by a focusing nozzle and then a high-frequency laser (in general, a 10 Hz-laser) is irradiated onto the fine particle. However, in such a mode, since hitting efficiency representing exact hitting of fine particle by a laser is very low, a LIBS spectrum for the single particle is obtained only in a part of several thousand shots. Accordingly, particle measurement efficiency is degraded, and the unnecessary blank spectrum occupies the most part of data. In addition, when a specific event (Asian Dust event or local pollution event) occurs, the particle measurement according to the free-firing mode may be not effective when quickly detecting particles or distinguishing between particles.